Tac/Scan is a unique game in that the player controls just how many resources (in this case, ships) are put into play. He starts with seven individual ships in play. Those ships can be lost in any of the three stages by hitting a tunnel, getting shot, or colliding with an enemy, the laser-firing Ahmins composing the superfleet from the planet of Ahm. The player is able to "collect" and earn these ships back as the game progresses. He can drop down to one ship in the game, but still have four "back-up" ships. If he loses the one ship in play however, the game is over. This is different from other games that give the player ships sequentially.

In the first stage, the player pilots his ships through waves of attacking enemies. He can either fire upon them, or "tac" his ships around them. The second stage is much like the first, except that it is from a 3-D perspective from behind the player's ships. In the third stage, the player pilots his ship down a space warp tunnel, and will lose any ships that touch the side of the tunnel.